As population increases, and as the use of the telephone system grows to accommodate new, non-traditional uses of switched telephone connections such as facsimile transmission, internet traffic, and related non-voice, data applications, the existing 7-digit numbering scheme for local calling is coming under increased stress. Under the existing North American numbering plan, which addresses any given telephone location by (NXX)N23-4567, where N is a digit from 2 to 9, X is any digit from 0 to 9, NXX is an area code, and N23-4567 designates a 7-digit phone number with central office prefix N23, a single area code, in theory, can only accommodate up to 8 million numbers (1 million based on the last six digits, times 8, for a first digit between 2 and 9). This is further restricted, since any given central office prefix N23, which is addressed through a single central office, and which can accommodate up to ten thousand numbers, may be under-utilized, for example, in a rural area where a central office of given N23 prefix may only serve a few hundred or a few thousand telephones. With competition developing in local loops, the so-called "CLECs" (Competitive Local Exchange Carriers) are obtaining given N23 prefixes for their own central offices, exerting further pressure on our numbering supplies. The depletion of available numbers in an area code is called "Area Code Exhaust". The process of replenishing the number supply in a numbering plan area is called "Area Code Relief".
Current solutions for Area Code Relief (splits and standard overlays) create, rather than solve, problems for customers. Recently, the widespread use of these methods has resulted in what can readily be described as a "National Area Code Disaster." Our dialing landscape has been damaged, and this damage has been expensive and disruptive for businesses and consumers. Some of the impacts from these current relief methods are outlined below.
FIGS. 1, 1A illustrate an established area code (818, as an example) before being impacted by area code relief. One solution which has been utilized, is so-called area code splitting, which is illustrated by FIGS. 2, 2A. In this solution, a geographic boundary is cut through the existing area code, the original area code (e.g. 818) is maintained on one side of the boundary, and a new area code (e.g., 626) is established on the other side of the boundary. This approach, however, is highly disruptive to telephone users both within and outside of the affected area code. Telephone owners in the new 626 area code effectively change to a new phone number overnight, and are forced to reprint letterheads, business cards, advertisements, directory listings, etc., in order to advise callers of their new area code. Callers both inside and outside the affected area code must adjust to the disrupted dialing patterns, including becoming familiar with the new numbers. Autodialers calling into the new area code, and from the new area code into the old area code, must be reprogrammed. Perhaps the only aspect of local calling which survives, is that callers within the old area code and the newly created area code can still use a 7-digit number to dial other telephones within their own area code's boundaries. However, calls across the new border between the old area code and the new area code now require 1+10-digit dialing, and disruption occurs both within and outside of the pertinent area codes. Overall, area code splitting is cumbersome, disruptive, and expensive.
An area code split forces half of the customers in the affected area to give up their existing phone numbers, cuts abbreviated (7 digit) dialing areas in half, and permanently disrupts established dialing patterns both within the affected area and into the affected area from everywhere else in the world. The overall cost just for mopping up after a single area code split is estimated to be over 40 million dollars (this includes updating signs and stationary, reprogramming of burglar alarms, fire alarms and other auto dialing systems, notifying customers and friends of number changes, modifying local phone switches, etc.). This reshuffling of phone numbers creates confusion for customers, resulting in numerous missed or misdialed phone calls for many years to come.
Another solution, illustrated by FIGS. 3, 3A, is the standard overlay method. In this method, instead of the geographic split of FIGS. 2, 2A ,the new area code is "overlaid" on top of the original area code. The result is a form of "subscription-based," rather than "geographic" splitting. That is, once the original (or "parent") 818 area code (for example) nears saturation, many new local telephone subscribers will be given numbers in the new (or "child") area code, such as 626 in this example. Over time, telephones with the 626 area code and telephones with the 818 area code will be intermingled throughout the geographic area described by the original 818 area code's boundaries. A user who first subscribed to a telephone connection in the 818 area code before saturation (i.e., exhaust), and who subscribes after saturation, e.g., to a second telephone connection to run a facsimile machine, would possibly obtain a 626 number for the facsimile line, and thus could have lines with two different area codes under the same roof. Over time, the overlay area (i.e., that area served by both the parent (e.g. 818) and the child (e.g. 626) area codes) would have telephone numbers with both area codes interlaced throughout it, and a call across the street, or even within the same building, could well involve two (or more) area codes.
The advantage to this approach, is that nobody ever needs to "change" their telephone number. Existing subscribers keep their original (the "parent") area code, while new subscribers might obtain a number from the new ("child") area code. With this method, no one ever has to update advertising, letterhead etc., to inform customers and friends about the area code change, because only new subscribers would receive service in the new area code. In addition, this approach is transparent to people outside of the overlay area, whether receiving calls from, or dialing into, the overlay area. Thus, this overlay method is much less disruptive to existing subscribers than is the area code split of FIGS. 2, 2A.
The disadvantage of this method, is that it severely disrupts local dialing patterns. In particular, as illustrated, every call, even locally, now becomes a 1+10-digit call, in which the caller must supply an area code even for calls right across the street, or to the office upstairs in the same building. Thus, autodialers must be reprogrammed, directory listings must be reprinted with at least 10-digit numbers, small children or elderly or handicapped persons must learn or re-learn a more difficult dialing technique, and the simplicity of 7-digit dialing stands in peril of extinction. While the FCC mandate for dialing parity in overlays has been interpreted to require that 1+10 digit dialing be used for all overlay dialing, it would be desirable to achieve this required parity, if possible, by dialing fewer than 1+10 digits.
In summary, using standard overlays for relief also creates hardship for customers. Existing dialing patterns are disrupted for all customers in the affected area. Seven (7) digit abbreviated dialing is abandoned for less convenient (and very unpopular and controversial) 1+10 digit dialing. For all calls in a standard overlay scenario, the area code must be dialed before the 7 digit number, creating difficulty for customers--especially children, elderly, and handicapped. Many people have expressed concern that dialing multiple area codes for calls within a single geographic region will create a feeling of disunity for the area. The shift from 7 digit to 1+10 digit dialing also necessitates reprogramming for all burglar alarms, fire alarms and other automatic dialing systems which had previously been programmed with 7 digit numbers. Incomplete calls will occur when 7 digits are dialed without the area code, and it is likely that the wrong area code will often be used by mistake, which happens today even where area codes are not overlaid. And, the likelihood of misdialing at least one out of 10 or 11 digits is significantly greater than when only 7 digits are dialed (expect an increase of 42% for 10 digits and 57% 1+10 digits).
By disrupting established dialing patterns, area code splits and standard overlays cause hardship, confusion and expense for customers, and prompt numerous misdials and wrong numbers.
It would be desirable if area code relief could be achieved with a minimum of disruption and expense. For a solution to be "preferred" it would have to satisfy both the needs of the customer and the requirements of the telecommunications industry.